Silk
From Amazon
SLIP King Silk Pillowcase, Black - Slipsilk Pure Mulberry 22 Momme 100% Silk Pillow Case - Anti-Aging Anti-Sleep Crease Anti-bedhead
Cult Beauty
Slip Silk Pillowcase King (Various Colours) - Black
OnBuy
Slip Silk King Pillowcase, Black (20" x 36") - 100% Pure 22 Momme Mulberry Silk Pillowcase - Anti-Aging, Anti-BedHead, Anti-Sleep Crease